Optical measuring devices for measuring objects are known. A measuring instrument for determining the surface and thickness of objects comprising a polychromatic light source and an optical processor part having a dispersive component that disperses chromatically in a non-axial direction optical radiation directed at the object to be measured is known from EP 2 076 733 B1. In this device different wavelengths of the optical radiation are focused in the direction of the normal of the surface of the object at different heights. A second processor part for optical radiation directs light, which is reflected by the measurement object in the mirror-reflection direction, towards a detector, which is configured to determine a wavelength of maximum intensity in order to determine a surface height.